The young Turkish policeman who killed Russia's ambassador to Ankara this week had provided security for President Recep Tayyip Erdogan eight times since the July 15 failed coup, a report said on Wednesday.
Mevlut Mert Altintas, 22, fired nine bullets into ambassador Andrei Karlov at an art exhibition centre on Monday evening, before he himself was killed by Turkish police.
Altintas, a member of the Ankara anti-riot police for two-and-a-half years, had been on duty at eight events attended by Erdogan since July, the Hurriyet daily said.
At such events he was part of the second wave of Erdogan's security after the personal bodyguard team of the president, wrote Hurriyet's writer Abdulkadir Selvi, known for his contacts in the ruling elite.
Turkish Foreign Minister Mevlut Cavusoglu told US counterpart John Kerry in a phone call on Tuesday that Turkey believed the US-based cleric Fethullah Gulen, who it blamed for the July 15 coup bid, was behind the assassination plot.
Turkish authorities are now investigating possible links of Altintas to Gulen, including a school he attended that was run by the cleric's group.
Hurriyet's Selvi said that on the day of the July 15 coup, Altintas had called in sick to the police. But it was not clear what he did that night.
The security forces have now detained 13 people over the attack including close relatives of Altintas, Turkish media reports said.
Meanwhile, a team of 18 Russian investigators arrived in Ankara on Tuesday to take part in a joint probe inside Turkey, an unprecedented move agreed by President Recep Tayyip Erdogan and Russian counterpart Vladimir Putin.